On 8/8/07, David Cournapeau [EMAIL PROTECTED] wrote:
Charles R Harris wrote:
Anne,
On 8/8/07, *Anne Archibald* [EMAIL PROTECTED]
mailto:[EMAIL PROTECTED] wrote:
On 08/08/2007, Charles R Harris [EMAIL PROTECTED]
mailto:[EMAIL PROTECTED] wrote:
On 8/8/07,
On 8/9/07, Charles R Harris [EMAIL PROTECTED] wrote:
On 8/8/07, David Cournapeau [EMAIL PROTECTED] wrote:
Charles R Harris wrote:
Anne,
On 8/8/07, *Anne Archibald* [EMAIL PROTECTED]
mailto: [EMAIL PROTECTED] wrote:
On 08/08/2007, Charles R Harris [EMAIL PROTECTED]
Charles R Harris wrote:
Well, what you want might be very easy to do in python, we just need
to check the default alignments for doubles and floats for some of the
other compilers, architectures, and OS's out there. On the other hand,
you might not be able to request a c malloc that is
Charles R Harris wrote:
Ah, you want it in C.
What would be the use to get SIMD aligned arrays in python ?
David
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On 8/9/07, David Cournapeau [EMAIL PROTECTED] wrote:
Charles R Harris wrote:
Well, what you want might be very easy to do in python, we just need
to check the default alignments for doubles and floats for some of the
other compilers, architectures, and OS's out there. On the other hand,
On 8/9/07, David Cournapeau [EMAIL PROTECTED] wrote:
Charles R Harris wrote:
Ah, you want it in C.
What would be the use to get SIMD aligned arrays in python ?
If I wanted a fairly specialized routine and didn't want to touch the guts
of numpy, I would pass the aligned array to a C
On Thu, Aug 09, 2007 at 04:52:38PM +0900, David Cournapeau wrote:
Charles R Harris wrote:
Well, what you want might be very easy to do in python, we just need
to check the default alignments for doubles and floats for some of the
other compilers, architectures, and OS's out there. On
On 8/9/07, Stefan van der Walt [EMAIL PROTECTED] wrote:
It doesn't really matter where the memory allocation occurs, does it?
As far as I understand, the underlying fftw function has some flag to
indicate when the data is aligned. If so, we could expose that flag
in Python, and do something
On Tue, Aug 07, 2007 at 01:33:24AM -0400, Anne Archibald wrote:
Well, it can be done in Python: just allocate a too-big ndarray and
take a slice that's the right shape and has the right alignment. But
this sucks.
Could you explain to me why is this such a bad idea?
Stéfan
On 08/08/2007, Stefan van der Walt [EMAIL PROTECTED] wrote:
On Tue, Aug 07, 2007 at 01:33:24AM -0400, Anne Archibald wrote:
Well, it can be done in Python: just allocate a too-big ndarray and
take a slice that's the right shape and has the right alignment. But
this sucks.
Could you
On 8/8/07, Anne Archibald [EMAIL PROTECTED] wrote:
On 08/08/2007, Stefan van der Walt [EMAIL PROTECTED] wrote:
On Tue, Aug 07, 2007 at 01:33:24AM -0400, Anne Archibald wrote:
Well, it can be done in Python: just allocate a too-big ndarray and
take a slice that's the right shape and has
On 08/08/2007, Charles R Harris [EMAIL PROTECTED] wrote:
On 8/8/07, Anne Archibald [EMAIL PROTECTED] wrote:
Oh. Well, it's not *terrible*; it gets you an aligned array. But you
have to allocate the original array as a 1D byte array (to allow for
arbitrary realignments) and then align it,
Anne,
On 8/8/07, Anne Archibald [EMAIL PROTECTED] wrote:
On 08/08/2007, Charles R Harris [EMAIL PROTECTED] wrote:
On 8/8/07, Anne Archibald [EMAIL PROTECTED] wrote:
Oh. Well, it's not *terrible*; it gets you an aligned array. But you
have to allocate the original array as a 1D byte
My 64 bit linux on Intel aligns arrays, whatever the data type, on 16 byte
boundaries. It might be interesting to see what happens with the Intel and
MSVC comipilers, but I expect similar results.
According to the doc on the msdn, the data should be 16-bits aligned.
Matthieu
On 8/8/07, Matthieu Brucher [EMAIL PROTECTED] wrote:
My 64 bit linux on Intel aligns arrays, whatever the data type, on 16 byte
boundaries. It might be interesting to see what happens with the Intel and
MSVC comipilers, but I expect similar results.
According to the doc on the msdn, the
Charles R Harris wrote:
Anne,
On 8/8/07, *Anne Archibald* [EMAIL PROTECTED]
mailto:[EMAIL PROTECTED] wrote:
On 08/08/2007, Charles R Harris [EMAIL PROTECTED]
mailto:[EMAIL PROTECTED] wrote:
On 8/8/07, Anne Archibald [EMAIL PROTECTED]
mailto:[EMAIL PROTECTED]
For platforms without posix_memalign, I don't see how to
implement a memory allocator with an arbitrary alignment (more
precisely, I don't see how to free it if I cannot assume a fixed
alignement: how do I know where the real pointer is ?).
Visual Studio seems to offer a counter part (also
Anne Archibald wrote:
Well, it can be done in Python: just allocate a too-big ndarray and
take a slice that's the right shape and has the right alignment. But
this sucks. Stephen G. Johnson posted code earlier in this thread that
provides a portable aligned-memory allocator - it handles the
On 8/6/07, Anne Archibald [EMAIL PROTECTED] wrote:
On 06/08/07, David Cournapeau [EMAIL PROTECTED] wrote:
Well, when I proposed the SIMD extension, I was willing to implement the
proposal, and this was for a simple goal: enabling better integration
with many numeric libraries which need
On 8/3/07, David Cournapeau [EMAIL PROTECTED] wrote:
Here is what I can think of:
- adding an API to know whether a given PyArrayObject has its data
buffer 16 bytes aligned, and requesting a 16 bytes aligned
PyArrayObject. Something like NPY_ALIGNED, basically.
- forcing data
On 06/08/07, David Cournapeau [EMAIL PROTECTED] wrote:
Well, when I proposed the SIMD extension, I was willing to implement the
proposal, and this was for a simple goal: enabling better integration
with many numeric libraries which need SIMD alignment.
As nice as a custom allocator might be,
Anne Archibald wrote:
I have to agree. I can hardly volunteer David for anything, and I
don't have time to implement this myself, but I think a custom
allocator is a rather special-purpose tool; if one were to implement
one, I think the way to go would be to implement a subclass of ndarray
On 07/08/07, David Cournapeau [EMAIL PROTECTED] wrote:
Anne, you said previously that it was easy to allocate buffers for a
given alignment at runtime. Could you point me to a document which
explains how ? For platforms without posix_memalign, I don't see how to
implement a memory allocator
On Aug 4, 3:24 am, Anne Archibald [EMAIL PROTECTED] wrote:
It seems to me two things are needed:
* A mechanism for requesting numpy arrays with buffers aligned to an
arbitrary power-of-two size (basically just using posix_memalign or
some horrible hack on platforms that don't have it).
On 8/3/07, Charles R Harris [EMAIL PROTECTED] wrote:
On 8/3/07, David Cournapeau [EMAIL PROTECTED] wrote:
Andrew Straw wrote:
Dear David,
Both ideas, particularly the 2nd, would be excellent additions to
numpy.
I often use the Intel IPP (Integrated Performance Primitives)
Here's a hack that google turned up:
(1) Use static variables instead of dynamic (stack) variables
(2) Use in-line assembly code that explicitly aligns data
(3) In C code, use *malloc* to explicitly allocate variables
Here is Intel's example of (2):
; procedure
On 04/08/07, David Cournapeau [EMAIL PROTECTED] wrote:
Here's a hack that google turned up:
I'd avoid hacks in favour of posix_memalign (which allows arbitrary
degrees of alignment. For one thing, freeing becomes a headache (you
can't free a pointer you've jiggered!).
- Check whether a
On 8/3/07, David Cournapeau [EMAIL PROTECTED] wrote:
Andrew Straw wrote:
Dear David,
Both ideas, particularly the 2nd, would be excellent additions to numpy.
I often use the Intel IPP (Integrated Performance Primitives) Library
together with numpy, but I have to do all my memory
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